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(No Model.)

F. A. WESSEL.

AUTOMATIC STARTING SWITCH TOR ELECTRIC MOTORS.

No. 453,319. I Patented (T111192, 1891.

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WITNESSES 1N VENTOR v Farah mud fly (28s a! ATTORNEY UNITED STATESPATENT OFFICE.

FERDINAND A. VVESSEL, OF BROOKLYN, ASSIGNOR TO THE EXCELSIOR ELECTRICCOMPANY, OF NETV YORK, N. Y.

AUTOMATIC STARTING-SWITCH FOR ELECTRIC MOTORS.

SPECIFICATION forming part of Letters Patent No. 458,319, dated June 2,1891.

Application filed January 9, 1891. Serial No. 377,270- (No model.)

To all whom it may concern.-

Be it known that I, FERDINAND A. WEssnL, a citizen of the United States,and a resident of Brooklyn,in the county of Kings and State of New York,have invented a certain new and useful Automatic Starting-Switch forElectric Motors, of which the following is a specification.

My invention relates to starting-switches for electric motors, andespecially motors fed from constant-potential wires.

The object of my invention is to prevent damage to the motor by means ofa sudden flow of an excessive current through the same.

hen a motor-armature revolves at a slow rate of speed, its counterelectro-motive force is small, and hence it offers very littleresistance to the flow of current through it. As the speed rises thecounter electro-motive force gradually rises also until, when the normalspeed has been attained, there will be a normal flow of current throughsuch armature. It is, moreover, Well known that an increase of load willreduce the speed of the armature, and in reducing its counterelectromotive force will give rise to the flow of an abnormally strongcurrent therethrough. The effect of this abnormally-strong currentpassing through the armature when its speed is slow, either at startingor from overloading or any other cause, is the great liability to burnthe armature before it attains the requisite speed. To prevent thisdestructive tendency it has been customary heretofore to provide anartificial resistance placed into the armature connection and graduallythrown or cut out as the speed rises by a switch-lever operated by hand.

My present invention is designed to provide a means whereby theoperation of the device which throws said artificial resistance into andout of circuit shall be coincident with changes in the speed of themachine, the organization being such that as the speed rises theresistance will be thrown out of circuit" until finally, when normalspeed is reached, all or practically all of said resistance will be out,just as in the case of rheostatic switches operated by hand, whilewhenthe speed falls the resistance will automatically come into circuitto protect the armature, and will be all or practically all in circuittherewith when the motor is at rest oris running at a slow speed.

My present invention is confined to a special organization wherein thearmature of the motor is permitted an end-play in its bearings, and thework is connected with such armature in such way as to give anend-thrust to the armature of increasing amount as the speed of thearmature and theload rise. The arn'iature-shaft operates upon therheostatic switch, and a reverse movement of the shaft as the speedfalls is produced by means of a retracting-spring or other suitabledevice.

My invention provides an effective safeguard against damage to thearmature in case its speed should fall or the armature be brought torest from any unusual cause, and also avoidsthe necessity ofmanipulating the usual rheostatie switch by hand after the circuit hasbeen closed through the armature.

In the accompanying drawings I have shown what I consider the bestmeansof carrying my invention into effect.

In the drawing the figure is a diagrammatic representation of anorganization embodying the invention.

Referring to the drawing, it will be seen that the motor M is connectedwith the mains I F is the usual field-magnet, and A the usual rotaryarmature, included in the shunt-wire s, which leads from one mainthrough the brushes B B and the said armature and also through theartificial resistance 0' and switch lever or arm Z, togetherconstituting the starting or rheostatic switch, and thence to the othermain m. As shown, the leverl is insulated at i for obvious reasons.

At 5 is shown the usual main switch, which serves to throw the motorinto or out of circuit.

The armature A is mounted in journals j j, adapted to slide in theirbearings, and one of the journals bears, preferably by means of arounded abutment, as indicated at J, against one arm of the switch-leverZ, so as to cause the said lever or arm to move or turn when thearmature slides in its bearings, the said lever or arm being preferablyfulcrumed at to a link Z, supported by the motor-frame f. In order topush the armature and its journal back to their extreme position when nocurrent is passing through the field-magnets, I connect some partconnected to the sliding journals, preferably the lever Z, to the frameby a retracting-spring s. In order to govern the amount of resistancecut out by the rheostatic switch by the speed of the armature, I providea fan F, mounted on and arranged near one end of the shaft S of thearmature.

The operation of the apparatus thus de scribed is as follows: Thearmature is preferably kept centered, when no current passes, by thespring 5'. When the current is turned on and the motor started, the fanF, turning with the armature in the direction of arrow 1, will tend toforce the sliding armature-shaft S inward in the direction of the arrow2 and cause the rheostatic switch-lever to move in the direction ofarrow It will be noted that this tendency of the vanes of the fan F toforce the shaft inward, and consequently, through lever Z to cut outmore or less of the coils of the resistance r, is substantiallyproportional to the speed of the armature. The resistance interposed inthe armature-circuit will hence be entirely governed by the amount ofresistance required by the armature to counteract the destructive actionof the current from the mains. No matter when a variation of speedoccurs, due to a change of load or other causes, the rheostat will beadjusted automatically by the speed of the armature. A perfect governoror regulator is thus provided. This form of construction is well adaptedto electric fans, where the wings or vanes of the fan can perform thedouble f u notion of ventilation and a rheostat-ic governor.

IVhile I have shown herein What I consider the preferred form ofapparatus involving my invention, it is manifest that the same may begreatly modified in detail without departing from said invention, and Ido not Wish to be understood as confining myself to the precise detailsof construction hereinbefore described.

While I have described the armature-shaft itself as the shaft which isgiven an end-play through the increase in the resistance of the work tooperation atincreased speeds, it is obvious that any other shaft havingproper endplay and carrying or connected with the work so as to rotatetherewith and be given an endthrustbyt-heincreasedresistance of the workmight be employed. 7

\Vhat I claim as my invention is 1. The combination, with an electricmotor having its armature in a connection between constant potentialmains, of a rheostatic switch the whole or a greater part of whoseresistance is in circuit when the motor is at rest or running at slowspeed, a rotary shaft connected to the work and having an endplay underthe increased resistance of the work to rotation at high speeds, and aswitchlever or equivalent device engaged with or controlled by saidshaft in its movements in the manner described, so as to throw out theresistance as the speed increases.

2. The combination, substantially as described, with an electric motorhaving its armature in-a circuit between constant-po ten tial mains, ofan armature-shaft having an end-play, and a rheostatic switch engaged bysaid shaft and having the whole or the greater part of its resistance incircuit with the armature when the machine is at rest or running at slowspeed, whereby on end-thrust of the shaft by increase of load or fromother cause accompanying increase of speed the resistance may be thrownout of circuit as the speed rises.

53. The combination,with an electric motor, of an armature-shaft havingend-play, a fan on said shaft, and a rhe'ostatic switch controlled bythe end-play of said shaft and having the whole or the greater part ofits resistance in the armature-circuit when the motor is at rest orrunning at low speed.

4. The combination, substantially as described, of an electric motor runfrom a constant-potential main, a rheostatic switch in thearmature-circuit, an armature-shaft having end-play and connected tosaid rheostatic switch, a fan upon said shaft, and a spring orequivalent retractor resisting the end-thrust of the shaft under theinfluence of the fan when in rotation. I

Signed at New York, in the county of New York and State of New York,this 27th day of December, A. D. 1890.

FERDINAND A. \VESS ET.

Witnesses:

WM. H. CAPEL, T. F. CoUREY.

